Declutter of graphical TCAS targets to improve situational awareness

ABSTRACT

Traffic collision and avoidance systems and methods for a host aircraft. The system receives traffic information from one or more target aircraft, determines threat levels of target aircraft associated with the received traffic information, generates one or more objects based on the determined threat levels and a pre-defined threat level, and displays the generated one or more objects that are associated with threat levels within the pre-defined threat level. A first indicator that indicates lateral position relative to the host aircraft and a second indicator that indicates vertical direction of travel of the associated target aircraft are also displayed.

PRIORITY CLAIM

This is a continuation application of U.S. patent application Ser. No.10/907,428 filed Mar. 31, 2005 now U.S. Pat. No. 7,307,578 and isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Current aircraft display systems represent Terrain Collision AvoidanceSystem (TCAS) target information using a standardized set of graphicalsymbols, see FIG. 1. However, present composite displays (horizontal andvertical situation displays) may be cluttered at times of high traffic,thus making it difficult to determine the location of true threats.

Also, in present vertical situation displays, it is impossible todetermine whether a displayed target is left or right of the aircraft'spresent flight path/plan.

Therefore, there exists a need for improving presentation of TCAS targetinformation on composite displays.

SUMMARY OF THE INVENTION

The present invention provides traffic collision and avoidance systemsand methods for a host aircraft. The host aircraft includes a receiverthat receives traffic information from one or more target aircraft, aprocessor that determines threat levels of target aircraft associatedwith the received traffic information, and generates one or more objectsbased on the determined threat levels and a pre-defined threat level,and a display that displays the generated one or more objects that areassociated with threat levels within the pre-defined threat level.

The display includes a vertical situation display with each displayedobject having a first indicator that indicates lateral position relativeto the host aircraft and a second indicator that indicates verticaldirection of travel of the associated target aircraft.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred and alternative embodiments of the present invention aredescribed in detail below with reference to the following drawings.

FIG. 1 illustrates a composite display formed in accordance with theprior art;

FIG. 2 is an example system formed in accordance with the embodiment ofthe present invention;

FIG. 3 illustrates targets to be presented on a composite display asformed in accordance with the embodiment of the present invention; and

FIG. 4 illustrates an example composite display that presents TCAStarget information in accordance with the embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention may be described in terms of functional blockdiagrams and various processing steps. Such functional blocks may berealized in many different forms of hardware, firmware, and/or softwarecomponents configured to perform the various functions. For example, thepresent invention may employ various integrated circuit components,e.g., memory elements, digital signal processing elements, look-uptables, and the like, which may carry out a variety of functions underthe control of one or more microprocessors or other control devices.Such general techniques are known to those skilled in the art and arenot described in detail herein. Moreover, it should be understood thatthe exemplary process illustrated may include additional or fewer stepsor may be performed in the context of a larger processing scheme.Furthermore, the various methods presented in the figures or thespecification are not to be construed as limiting the order in which theindividual processing steps may be performed. The particularimplementations shown and described herein are illustrative of theinvention and its best mode and are not intended to otherwise limit thescope of the invention in any way.

In FIG. 2, an exemplary display system 100 includes a graphics processor102 configured to provide information to a display device 104. One ormore data sources are coupled to the processor 102. These data sourcesmay be, but are not limited to a terrain database 106, a weather radardata source 108 from and on-board weather radar unit or from an externalweather data source such as a ground-based weather data source or asatellite weather data source, a terrain avoidance and warning system(TAWS) 110, a navigation database 112, a traffic collision and avoidancesystem (TCAS) 114 or other sensors 116 which may provide additionaluseful information to a user.

A number of aspects of the display device 104 (which are controlled bythe processor 102 in a practical embodiment) may contribute to theimproved contents and appearance of the display, thus increasing thesituational awareness of the pilot and/or flight crew. The imagegeneration and display aspects may leverage known techniques such thatexisting display systems can be modified in a straightforward manner tosupport the different features described herein. In a practicalimplementation, the concepts described herein may be realized in theform of revised display generation software or processing resident atthe processor 102 or at the TCAS 114.

The processor 102 encompasses one more functional blocks used to providea flight management, navigational, weather and positional interface withthe pilot, and input to the display device 104. The processor 102 mayinclude or cooperate with a mode, position and/or detection element thatis capable of determining the mode or position of the vehicle relativeto one or more reference locations, points, planes, or navigation aids.In addition, the processor 102 may be configured to receive, analyze,condition, and process navigation and positional information as well asweather information associated with the vehicle. In this regard, theprocessor 102 may include any number of individual microprocessors,flight computers, navigation equipment, memories, storage devices,interface cards, and other standard components known in the art.Moreover, the processor 102 may include any number of microprocessorelements, memory elements, power supplies, and other functionalcomponents as necessary to support the operation of the display system100. In this respect, the processor 102 may include or cooperate withany number of software programs or instructions designed to carry outvarious methods, process tasks, calculations, control functions, and thegeneration of display signals and other data used by the display device104. For example, the processor 102 may be configured to generate anannunciation associated with the position of the aircraft relative to atleast one reference location, to generate windows corresponding to userinputs, to combine inputs from various sensors to create a single datastream for presentation to the display device 104, and the like.

The processor 102 may also be suitable configured to receive and processnavigational data related to an intended destination of the aircraft. Ina practical commercial aircraft application, such navigational data maybe associated with specific waypoints, airports, navigational aids, orthe like. The processor 102 may process data from any of the data inputsshown above and generate appropriate signals to the display device 104such that the display device 104 generates indicia representative of theappropriate navigational, weather, terrain, or other information, or thelike. Such processors and flight control computers are available from anumber of manufacturers such as Honeywell International Inc. In anexemplary embodiment, the processor 102 is incorporated within a flightmanagement system (FMS) or another avionics component which, inter alia,formats navigation and traffic data and forwards the data to the displaydevice 104 for display.

The display device 104 may include any display element suitable fordisplaying the various symbols and information detailed below. Manycurrently known monitors are suitable for this task, including variousCRT and flat-panel display systems. Display device 104 may be based on apanel mounted display, a heads-up display (HUD) projection, or any knowntechnology. In an exemplary embodiment, the display device 104 includesa panel display. In one embodiment, the display device 104 is acomposite display having multiple view displays, one of which is avertical situation display. Also, the display device 104 may a verticalsituation mode of display.

In operation, the processor 102 obtains inertial data (position, speed,direction) from the sensors 116. Based on the inertial data, theprocessor 102 obtains terrain data and navigation data from thedatabases 106, 112. These databases are typically onboard the aircraft,but need not be limited to such a design. The processor 102 renders apicture of the absolute terrain, and the navigation data (VHF (Very HighFrequency) Omni-directional Radio-range (VORs), airports, airways, etc.)is also rendered on the display device 104. Overlaid on top of thispicture is data from the TCAS 114, the TAWS 110 and the weather datasource 108. The TCAS 114 provides information regarding other aircraftlocated in the vicinity. The TCAS data may consist of, but is notlimited to, speed, direction, altitude, and altitude trend. Eachaircraft is drawn on the display device 104 by the processor 102. In oneembodiment, only icons associated with other aircraft that meet acertain threat level criteria are presented on the display device 104.Also, the relative position, vertical velocity and threat level of theother aircraft are used to determine what aspects of display icons togenerate and display of a vertical situation display. The weather datasource 108 provides the location of weather cells to the processor 102.This data consists of the location of precipitation which is shown invarious colors on the display based on the water content of the weathercells. The processor 102 renders the location of the cells on thedisplay. The TAWS 110 provides data to the processor 102 regarding thelocation of terrain that may be a threat to the aircraft. The processor102 may show the potential threat terrain in various colors depending onthe level of threat: red for warnings (immediate danger), yellow forcautions (possible danger), and green for terrain that is not a threat.

FIG. 3 illustrates various display objects 160 that are generated byeither the TCAS 114 or the processor 102. The display objects 160 arepresented on a vertical situation display where their position on thedisplay indicates altitude of associated aircraft. The objects 160 alsoindicate lateral information relative to the operating aircraft andparticular relevance (i.e., threat level) as determined by the TCAS 114.In this embodiment, the display objects 160, are circles 162-168 thatappear to include an equator line 170-176 that gives each of the circles162-168 a spherical appearance. The equator lines 170-176 appear asovals within the circles 162-168. The ovals include a top half and abottom half. The top half of the equator lines is assumed in thisembodiment to be on a back side of a sphere, assuming the circle is asphere and the bottom half of the oval resides on the front half of thesame sphere.

With regard to the first circle 162 and the fourth circle 168, theequator lines 170 and 176 have top and bottom halves that have equaldisplay intensity within the respective circle 162 and 168, thus meaningthat the aircraft associated with the circles 162 and 168 are locatedwithin a threshold distance from the host aircraft's present flightpath/plan.

A second circle 164 includes an equator line 172 with the bottom halfhaving a greater intensity than the top half. Therefore, when the circle164 is presented within the vertical situation display, the circle 164indicates that the aircraft associated with the object 164 is greaterthan a threshold distance to the starboard or right of the aircraft'sflight path/plan. The reverse is true for the third circle 166 thatshows that the top half of the equator line 174 is brighter than thebottom half of the equator line 174.

The objects 160 may also present other information, such as threat leveland relative importance of the threat. In the composite display shown inFIG. 1, the circles 162-168 are applied a color depending upon thethreat level of associated target aircraft. In one embodiment, the samecolor scheme is used in the present invention and applied to the objects160. For example, red indicates the highest threat level followed byamber and then blue. This will be illustrated in more detail below withregard to FIG. 4.

Display intensity of the color of the icons identifies threat level ofthe associated threat aircraft. This also will be shown by example inmore detail below in FIG. 4. Also, the size of the objects 160 furtherindicates the threat level of an associated target aircraft. This alsowill be shown in more detail below in FIG. 4.

FIG. 4 illustrates a composite display 200 formed in accordance with anembodiment of the present invention. The composite display 200 includesa horizontal situation display 204 and a vertical situation display 206.As shown in the horizontal situation display 204, a high alert icon 210,two medium alert icons 212 and 214, as well as numerous low priorityTCAS icons are displayed. The high priority icon 210 is displayed inred. The medium priority icons 212 and 214 are displayed as amber iconsand the remaining TCAS icons are displayed as blue. All icons that aredisplayed as red or yellow in the horizontal situation display 204 ispresented within the vertical situation display 206 with the same color.

When the vertical situation display 206 is in a filter mode, as selectedby a pull-down menu 240 or selected or activated by some othercomparable means, only the targets associated with objects that arepresented in the horizontal situation display 204 that are within athreshold threat value are presented. In one embodiment, the filteringof targets is calculated using a historical record of target and hostaircraft direction vectors. The host aircraft's direction vector iscompared to target aircraft direction vectors and if the comparisonindicates that a target aircraft direction vector is not within athreshold (i.e., angular threshold), the target is completely removedfrom being displayed. As shown in the vertical situation display 206 twoblue icons 230 and 232 are shown aft of an aircraft icon 216 thatrepresents the host aircraft. The icons 230 and 232 include equatorlines with bottom halves having greater intensity than top halves,thereby meaning that the associated target aircraft are to the right ofthe aircraft's line of flight. Also, the icon 230 has greater intensitythan the icon 232, thus meaning that the aircraft associated with theicon 230 is more of a threat than the aircraft associated with the icon232. The level of threat is assessed by a number of parameters, such asspeed, direction of travel relative to the host aircraft, altitude, andother factors. In one embodiment, the level of threat is determined bythe TCAS 114.

Also shown in the vertical situation display 206 may display icons ofvarious sizes, such as icons 220 and 222. Aircraft associated withsmaller icons have a lower threat level than aircraft associated withlarger icons.

Also shown are transparent blue icons. Aircraft associated withtransparent blue icons have a lessor threat value than those associatedwith solid blue icons.

A red icon 210 a corresponds to the icon 210, an amber icon 214 acorresponds to the icon 214 and an amber icon 212 a corresponds to theamber icon 212 in the horizontal situation display 204. The icon 214 aindicates that it is to the right of the aircraft's flight path/planbecause the bottom half of the equator line is of higher intensity thanthe top half of the equator line and the amber icon 212 a is to the leftof the aircraft's flight path/plan, because the top half of the equatorline is of a greater intensity than the bottom half.

Thus, it is easy for the flight crew to interpret the visual cuespresented in the vertical situation display 206. If the flight crewwants to determine what aircrafts are presently along their flightpath/plan, they just look for all of the icons with equator lines ofconstant intensity between the top and bottom halves. In this examplethat includes icons 210 a and 234. It is also easy to see the altitudesof target aircraft of various threat levels.

In one embodiment, the icons presented within the vertical situationdisplay 206 also include a vertical motion indicator 250. If thevertical motion indicator 250 creates an arrow that points to the top ofthe vertical situation display 206, then the aircraft associated withthat icon is climbing. And of course if the vertical motion indicator250 is an arrow that points down, the aircraft is descending. If thevertical motion indicator 250 does not point up or down or is notdisplayed, then the associated target aircraft is flying straight andlevel.

The present invention may be implemented on various aircraft displays,such as a Primary Flight Display (PFD), Lateral Map, Vertical Map,Horizonal Situation Indicator (HIS), Advanced Vision System (AVS), orany perspective display device.

While the preferred embodiment of the invention has been illustrated anddescribed, as noted above, many changes can be made without departingfrom the spirit and scope of the invention. For example, the icons maybe various shapes, sizes, or colors provided they present comparableinformation as that shown and described above. Accordingly, the scope ofthe invention is not limited by the disclosure of the preferredembodiment. Instead, the invention should be determined entirely byreference to the claims that follow.

1. A traffic collision and avoidance method for a host aircraft, themethod comprising: receiving traffic collision and avoidance informationfrom one or more targets; filtering the one or more targets based on athreshold value; and displaying one or more objects that are associatedwith one or more target aircraft that remain after filtering on avertical situation display, wherein displaying includes displaying theobjects in one of two or more sizes based on threat level informationincluded in the traffic collision and avoidance information andpresenting in a vertical profile view; and wherein the threshold valueincludes a position threshold value and a threat threshold value,wherein displaying includes indicating lateral direction relative to thehost aircraft using a graphical object having an equator line, theequator line includes two halves, when a first one of the two halves isdisplayed in a first manner, the associated target aircraft is laterallyleft of the host aircraft, when the second one of the two halves isdisplayed in the first manner, the associated target aircraft islaterally right of the host aircraft, when one of the halves isdisplayed in the first manner, the other halve is displayed in adifferent manner.
 2. The method of claim 1, wherein filtering includesfiltering based on a direction vector information included in thereceived traffic collision and avoidance information and a directionvector of the host aircraft.
 3. The method of claim 1, whereindisplaying includes indicating vertical direction of travel of theassociated target aircraft.
 4. The method of claim 1, wherein indicatingthreat level includes displaying the object in one of two or more colorsbased on an identified threat level.
 5. The method of claim 4, whereinthe colors include at least two of blue, amber, red or cyan.
 6. Themethod of claim 1, wherein displaying includes displaying the object inone of two or more transparency levels based on angular informationincluded in the traffic collision and avoidance information.
 7. Themethod of claim 1, wherein displaying includes displaying the object inone of two or more color fade levels based on angular informationincluded in the traffic collision and avoidance information.
 8. Atraffic collision and avoidance system for a host aircraft, the systemcomprising: a receiver for receiving traffic information from one ormore target aircraft; a processor coupled to the receiver fordetermining threat levels of target aircraft associated with thereceived traffic information, filtering the one or more target aircraftbased on a threshold value, and generating one or more objects based onthe filtering; and a vertical situation display coupled to the processorfor displaying the generated one or more objects that are associatedwith threat levels within the pre-defined threat level, wherein thedisplayed objects are displayed in one of two or more sizes based onthreat level information and are presented in a vertical profile view;and wherein the threshold value includes a position threshold value anda threat threshold value, wherein each of the displayed objects includesa graphical object having an equator line, the equator line includes twohalves, when a first one of the two halves is displayed in a firstmanner, the associated target aircraft is laterally left of the hostaircraft, when the second one of the two halves is displayed in thefirst manner, the associated target aircraft is laterally right of thehost aircraft, when one of the halves is displayed in the first manner,the other half is displayed in a different manner.
 9. The system ofclaim 8, wherein the processor filters based on a direction vectorinformation included in the received traffic collision and avoidanceinformation and a direction vector of the host aircraft.
 10. The systemof claim 8, wherein the displayed objects include a second indicator forindicating vertical direction of travel of the associated targetaircraft.
 11. The system of claim 8, wherein the displayed objects aredisplayed in one of two or more colors based on the threat level. 12.The system of claim 11, wherein the colors include at least two of blue,amber, red, or cyan.
 13. The system of claim 8, wherein the displayedobjects are displayed in one of two or more transparency levels based onangular information included in the traffic collision and avoidanceinformation.
 14. The system of claim 8, wherein the displayed objectsare displayed in one of two or more color fade levels based on angularinformation included in the traffic collision and avoidance information.